779
FNCA52 TJSJ 211930
FWFSJU
FIRE WEATHER PLANNING FORECAST FOR PUERTO RICO
NATIONAL WEATHER SERVICE SAN JUAN PR
330 PM AST FRI AUG 21 2026
DISCUSSION
ELEVATED FIRE WEATHER CONDITIONS WILL CONTINUE THROUGH THE
REMAINDER OF THE AFTERNOON, PARTICULARLY ACROSS THE SOUTHERN
COASTAL PLAINS AND OTHER FIRE-PRONE AREAS OF PUERTO RICO. LOW RH
VALUES, BREEZY E-ESE WINDS, AND DRY FUELS WILL CONTINUE TO FAVOR
RAPID FIRE SPREAD. CONDITIONS SHOULD GRADUALLY IMPROVE THIS
EVENING AS WINDS DECREASE AND RH VALUES RECOVER. INCREASING
MOISTURE AND SHOWER ACTIVITY FROM SATURDAY ONWARD SHOULD FURTHER
REDUCE THE FIRE WEATHER THREAT.
PRZ014-220800-
SOUTHEAST COASTAL PLAINS-
330 PM AST FRI AUG 21 2026
TONIGHT SAT SAT NIGHT SUN
CLOUD COVER MCLEAR MCLEAR PCLDY MCLEAR
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 10 40 30 0
TEMP (24H TREND) 75 (-2) 93 (+2) 75 93
RH % (24H TREND) 88 (+9) 44 (-6) 87 46
WIND 20FT/EARLY(MPH) E 13 E 11 E 11 E 13
WIND 20FT/LATE(MPH) NE 9 SE 16 G24 NE 9 E 13 G21
MIXING HGT(FT-AGL/MSL) 4780 5810
TRANSPORT WND (MPH) E 16 E 17
VENT RATE (KT-FT) 66920 87150
DISPERSION 5 5
DSI 4 6 3 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ015-220800-
SOUTHERN HILLS-
330 PM AST FRI AUG 21 2026
TONIGHT SAT SAT NIGHT SUN
CLOUD COVER MCLEAR PCLDY MCLEAR MCLEAR
PRECIP TYPE SHOWERS TSTMS SHOWERS SHOWERS
CHANCE PRECIP (%) 10 50 20 30
TEMP (24H TREND) 71 (-3) 90 (+3) 71 90
RH % (24H TREND) 97 (+9) 55 (-4) 96 55
WIND 20FT/EARLY(MPH) NE 13 E 11 E 11 E 11
WIND 20FT/LATE(MPH) NE 11 E 13 NE 11 E 12
MIXING HGT(FT-AGL/MSL) 5740 6220
TRANSPORT WND (MPH) E 14 E 16
VENT RATE (KT-FT) 68880 87080
DISPERSION 5 5
DSI 3 6 3 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ016-220800-
NORTH COASTAL PLAINS-
330 PM AST FRI AUG 21 2026
TONIGHT SAT SAT NIGHT SUN
CLOUD COVER MCLEAR PCLDY PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 20 40 20 30
TEMP (24H TREND) 75 (-2) 91 (+2) 74 92
RH % (24H TREND) 96 (+9) 58 (-7) 96 58
WIND 20FT/EARLY(MPH) E 16 E 12 E 17 E 13
WIND 20FT/LATE(MPH) E 13 E 18 E 12 E 20
MIXING HGT(FT-AGL/MSL) 4670 5560
TRANSPORT WND (MPH) E 14 E 17
VENT RATE (KT-FT) 56040 83400
DISPERSION 5 5
DSI 5 6 5 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ017-220800-
NORTHERN HILLS-
330 PM AST FRI AUG 21 2026
TONIGHT SAT SAT NIGHT SUN
CLOUD COVER MCLEAR PCLDY MCLEAR PCLDY
PRECIP TYPE SHOWERS TSTMS SHOWERS TSTMS
CHANCE PRECIP (%) 10 50 10 60
TEMP (24H TREND) 72 (-2) 90 (+2) 71 90
RH % (24H TREND) 98 (+6) 60 (-4) 98 61
WIND 20FT/EARLY(MPH) E 14 E 10 E 13 E 12
WIND 20FT/LATE(MPH) E 12 NE 14 E 10 E 17
MIXING HGT(FT-AGL/MSL) 5830 6070
TRANSPORT WND (MPH) E 12 E 14
VENT RATE (KT-FT) 58300 72840
DISPERSION 5 5
DSI 4 6 3 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ018-220800-
WEST COAST-
330 PM AST FRI AUG 21 2026
TONIGHT SAT SAT NIGHT SUN
CLOUD COVER MCLEAR PCLDY MCLEAR MCLEAR
PRECIP TYPE SHOWERS TSTMS SHOWERS TSTMS
CHANCE PRECIP (%) 10 50 10 40
TEMP (24H TREND) 73 (-1) 94 (+3) 72 93
RH % (24H TREND) 97 (+6) 57 (-6) 98 57
WIND 20FT/EARLY(MPH) E 17 E 12 E 12 E 12
WIND 20FT/LATE(MPH) E 17 E 12 E 11 E 13
MIXING HGT(FT-AGL/MSL) 5000 5250
TRANSPORT WND (MPH) E 8 E 12
VENT RATE (KT-FT) 35000 52500
DISPERSION 5 5
DSI 4 6 3 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ019-220800-
EASTERN INTERIOR-
330 PM AST FRI AUG 21 2026
TONIGHT SAT SAT NIGHT SUN
CLOUD COVER PCLDY PCLDY PCLDY MCLEAR
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 30 40 40 30
TEMP (24H TREND) 73 (-3) 90 (+2) 73 91
RH % (24H TREND) 97 (+9) 57 (-4) 97 58
WIND 20FT/EARLY(MPH) E 13 E 11 E 11 E 12
WIND 20FT/LATE(MPH) E 13 E 13 E 12 E 13
MIXING HGT(FT-AGL/MSL) 5660 6870
TRANSPORT WND (MPH) E 14 E 16
VENT RATE (KT-FT) 67920 96180
DISPERSION 5 5
DSI 3 6 3 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ022-220800-
LUQUILLO MOUNTAIN RANGE-
330 PM AST FRI AUG 21 2026
TONIGHT SAT SAT NIGHT SUN
CLOUD COVER PCLDY PCLDY PCLDY PCLDY
PRECIP TYPE SHOWERS TSTMS SHOWERS SHOWERS
CHANCE PRECIP (%) 30 50 40 40
TEMP (24H TREND) 70 (-4) 86 (+4) 70 85
RH % (24H TREND) 100 (+10) 63 (-7) 100 65
WIND 20FT/EARLY(MPH) E 11 E 10 E 9 E 11
WIND 20FT/LATE(MPH) E 10 E 11 E 9 E 11
MIXING HGT(FT-AGL/MSL) 4640 4930
TRANSPORT WND (MPH) E 14 E 17
VENT RATE (KT-FT) 55680 73950
DISPERSION 5 5
DSI 4 6 5 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ023-220800-
CENTRAL MOUNTAIN RANGE-
330 PM AST FRI AUG 21 2026
TONIGHT SAT SAT NIGHT SUN
CLOUD COVER MCLEAR PCLDY MCLEAR PCLDY
PRECIP TYPE SHOWERS TSTMS SHOWERS TSTMS
CHANCE PRECIP (%) 10 60 0 60
TEMP (24H TREND) 68 (-3) 88 (+4) 68 88
RH % (24H TREND) 100 (+6) 61 (-4) 99 61
WIND 20FT/EARLY(MPH) E 13 E 9 E 10 E 9
WIND 20FT/LATE(MPH) E 12 E 10 E 8 E 10
MIXING HGT(FT-AGL/MSL) 6750 6790
TRANSPORT WND (MPH) E 10 E 14
VENT RATE (KT-FT) 60750 81480
DISPERSION 5 5
DSI 2 6 2 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ024-220800-
CAYEY MOUNTAIN RANGE-
330 PM AST FRI AUG 21 2026
TONIGHT SAT SAT NIGHT SUN
CLOUD COVER MCLEAR PCLDY PCLDY MCLEAR
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 30 40 40 20
TEMP (24H TREND) 71 (-3) 86 (+2) 70 86
RH % (24H TREND) 99 (+7) 62 (-2) 99 63
WIND 20FT/EARLY(MPH) NE 12 E 10 E 9 E 11
WIND 20FT/LATE(MPH) E 9 E 12 E 9 E 11
MIXING HGT(FT-AGL/MSL) 5290 5820
TRANSPORT WND (MPH) E 15 E 17
VENT RATE (KT-FT) 68770 87300
DISPERSION 5 5
DSI 3 6 3 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ025-220800-
VIEQUES-
330 PM AST FRI AUG 21 2026
TONIGHT SAT SAT NIGHT SUN
CLOUD COVER PCLDY PCLDY PCLDY MCLEAR
PRECIP TYPE SHOWERS TSTMS SHOWERS SHOWERS
CHANCE PRECIP (%) 30 50 50 20
TEMP (24H TREND) 78 (-3) 91 (+3) 79 91
RH % (24H TREND) 83 (+6) 55 (-7) 82 56
WIND 20FT/EARLY(MPH) E 17 E 13 E 14 E 14
WIND 20FT/LATE(MPH) E 17 E 13 E 14 E 13
MIXING HGT(FT-AGL/MSL) 3450 3420
TRANSPORT WND (MPH) E 15 E 18
VENT RATE (KT-FT) 44850 54720
DISPERSION 5 5
DSI 6 6 6 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ026-220800-
CULEBRA-
330 PM AST FRI AUG 21 2026
TONIGHT SAT SAT NIGHT SUN
CLOUD COVER PCLDY PCLDY PCLDY MCLEAR
PRECIP TYPE SHOWERS TSTMS SHOWERS SHOWERS
CHANCE PRECIP (%) 30 50 40 20
TEMP (24H TREND) 79 (-2) 91 (+3) 79 92
RH % (24H TREND) 89 (+9) 58 (-9) 87 59
WIND 20FT/EARLY(MPH) E 17 E 13 E 14 E 14
WIND 20FT/LATE(MPH) E 17 E 12 E 14 E 13
MIXING HGT(FT-AGL/MSL) 3390 3330
TRANSPORT WND (MPH) E 16 E 20
VENT RATE (KT-FT) 47460 56610
DISPERSION 5 5
DSI 6 6 6 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ027-220800-
SOUTHWEST COASTAL PLAINS AND MONA ISLAND-
330 PM AST FRI AUG 21 2026
TONIGHT SAT SAT NIGHT SUN
CLOUD COVER MCLEAR MCLEAR MCLEAR MCLEAR
PRECIP TYPE NONE SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 0 40 10 10
TEMP (24H TREND) 74 (-3) 94 (+4) 74 94
RH % (24H TREND) 89 (+11) 49 (-4) 87 47
WIND 20FT/EARLY(MPH) E 14 E 13 E 11 E 14 G22
WIND 20FT/LATE(MPH) E 16 SE 14 G23 E 10 SE 17 G25
MIXING HGT(FT-AGL/MSL) 5050 5560
TRANSPORT WND (MPH) E 16 E 18
VENT RATE (KT-FT) 70700 88960
DISPERSION 5 5
DSI 3 6 3 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
VIZ001-220800-
SAINT THOMAS AND SAINT JOHN-
330 PM AST FRI AUG 21 2026
TONIGHT SAT SAT NIGHT SUN
CLOUD COVER PCLDY PCLDY PCLDY MCLEAR
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 30 40 30 20
TEMP (24H TREND) 78 (-3) 90 (+3) 78 90
RH % (24H TREND) 89 (+9) 58 (-7) 87 59
WIND 20FT/EARLY(MPH) E 17 E 14 E 16 E 14
WIND 20FT/LATE(MPH) E 17 E 13 E 16 E 13
MIXING HGT(FT-AGL/MSL) 3270 3270
TRANSPORT WND (MPH) E 16 E 21
VENT RATE (KT-FT) 45780 58860
DISPERSION 5 5
DSI 6 6 6 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
VIZ002-220800-
ST CROIX-
330 PM AST FRI AUG 21 2026
TONIGHT SAT SAT NIGHT SUN
CLOUD COVER MCLEAR PCLDY PCLDY MCLEAR
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 20 30 30 20
TEMP (24H TREND) 78 (-3) 90 (+2) 78 90
RH % (24H TREND) 86 (+5) 60 (-6) 86 62
WIND 20FT/EARLY(MPH) E 16 E 14 E 16 E 14
WIND 20FT/LATE(MPH) E 16 E 12 E 16 E 13
MIXING HGT(FT-AGL/MSL) 4710 4950
TRANSPORT WND (MPH) E 16 E 20
VENT RATE (KT-FT) 65940 84150
DISPERSION 5 5
DSI 6 6 6 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
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